Semiconductor device and method for manufacturing the same

Abstract

In the transistor including an oxide semiconductor film, which includes a film for capturing hydrogen from the oxide semiconductor film (a hydrogen capture film) and a film for diffusing hydrogen (a hydrogen permeable film), hydrogen is transferred from the oxide semiconductor film to the hydrogen capture film through the hydrogen permeable film by heat treatment. Specifically, a base film or a protective film of the transistor including an oxide semiconductor film has a stacked-layer structure of the hydrogen capture film and the hydrogen permeable film. At this time, the hydrogen permeable film is formed on a side which is in contact with the oxide semiconductor film. After that, hydrogen released from the oxide semiconductor film is transferred to the hydrogen capture film through the hydrogen permeable film by the heat treatment.

What is claimed is: 
     
       1. A method for manufacturing a semiconductor device comprising the steps of:
 forming a base film over a substrate; 
 forming an oxide semiconductor film over the base film; 
 performing a heat treatment so as to release hydrogen from the oxide semiconductor film; 
 forming a pair of electrodes over and in contact with at least a part of the oxide semiconductor film; 
 forming a gate insulating film over the oxide semiconductor film; and 
 forming a gate electrode over the oxide semiconductor film with the gate insulating film provided therebetween, 
 wherein the base film comprises a hydrogen capture film and a hydrogen permeable film which are stacked in this order, 
 wherein the hydrogen capture film comprises an oxynitride film containing indium, and 
 wherein the hydrogen permeable film comprises a silicon oxide film or a silicon oxynitride film. 
 
     
     
       2. The method for manufacturing a semiconductor device according to  claim 1 ,
 wherein the hydrogen released from the oxide semiconductor film is transferred to the hydrogen capture film through the hydrogen permeable film by the heat treatment. 
 
     
     
       3. The method for manufacturing a semiconductor device according to  claim 1 ,
 wherein the hydrogen permeable film comprises an oxide film, and 
 wherein oxygen is transferred from the hydrogen permeable film to the oxide semiconductor film by performing the heat treatment. 
 
     
     
       4. The method for manufacturing a semiconductor device according to  claim 1 ,
 wherein the hydrogen capture film and the oxide semiconductor film comprise at least a metal element, and 
 wherein the hydrogen permeable film does not include the metal element. 
 
     
     
       5. The method for manufacturing a semiconductor device according to  claim 1 ,
 wherein the oxide semiconductor film comprises an In—Ga—Zn—O based film, and 
 wherein the hydrogen capture film comprises an In—Ga—Zn—O—N based film. 
 
     
     
       6. The method for manufacturing a semiconductor device according to  claim 1 ,
 wherein a thickness of the hydrogen permeable film is less than or equal to 5 nm. 
 
     
     
       7. The method for manufacturing a semiconductor device according to  claim 1 ,
 wherein a temperature of the heat treatment is higher than 450° C. and lower than a strain point of the substrate. 
 
     
     
       8. The method for manufacturing a semiconductor device according to  claim 1 ,
 wherein a hydrogen concentration in the hydrogen capture film is greater than or equal to 1×10 19  cm −3  and less than or equal to 5×10 20  cm −3  after the heat treatment. 
 
     
     
       9. The method for manufacturing a semiconductor device according to  claim 1 , further comprising the step of:
 adding an impurity to the part of the oxide semiconductor film. 
 
     
     
       10. A method for manufacturing a semiconductor device comprising the steps of:
 forming a first insulating film over a substrate; 
 forming an oxide semiconductor film over the first insulating film; 
 forming a pair of electrodes over and in contact with at least part of the oxide semiconductor film; 
 forming a second insulating film over the oxide semiconductor film and the pair of electrodes; and 
 performing a heat treatment, 
 wherein one of the first insulating film and the second insulating film comprises a third insulating film and a fourth insulating film which are stacked, the third insulating film being adjacent to the oxide semiconductor film, 
 wherein hydrogen is transferred from the oxide semiconductor film to the fourth insulating film through the third insulating film by the heat treatment, 
 wherein the hydrogen is captured by the fourth insulating film, and 
 wherein the fourth insulating film comprises an oxynitride film containing indium. 
 
     
     
       11. The method for manufacturing a semiconductor device according to  claim 10 ,
 wherein the third insulating film comprises an oxide film, and 
 wherein oxygen is transferred from the third insulating film to the oxide semiconductor film by performing the heat treatment. 
 
     
     
       12. The method for manufacturing a semiconductor device according to  claim 10 ,
 wherein the fourth insulating film and the oxide semiconductor film comprise at least a metal element, and 
 wherein the third insulating film does not include the metal element. 
 
     
     
       13. The method for manufacturing a semiconductor device according to  claim 10 ,
 wherein the third insulating film comprises a silicon oxide film or a silicon oxynitride film. 
 
     
     
       14. The method for manufacturing a semiconductor device according to  claim 10 ,
 wherein the oxide semiconductor film comprises an In—Ga—Zn—O based film, and 
 wherein the fourth insulating film comprises an In—Ga—Zn—O—N based film. 
 
     
     
       15. The method for manufacturing a semiconductor device according to  claim 10 ,
 wherein a thickness of the third insulating film is less than or equal to 5 nm. 
 
     
     
       16. The method for manufacturing a semiconductor device according to  claim 10 ,
 wherein a temperature of the heat treatment is higher than 450° C. and lower than a strain point of the substrate.